236 BOTANICAL GAZETTE [SEPTEMBER 
the petiole and laid on a table. The rest of the cortex was peeled off 
and the core laid next to the strip. When the elongation of the core 
and the contraction of the strip had ceased, both were measured and the 
results assembled. For the second set of experiments, petioles were col- 
lected in the early morning and soaked for about 40 minutes in tap water 
to make sure that they were turgid. In the experiment three lengths 
were employed: “20, 25, and 30 cm., with each following the same 
methods as above. The results of both sets, summarized in tabular form, 
are shown in the accompanying table. 
TABLE I 
TABLE OF TISSUE TENSION IN Amor phophallus 
LENGT 
Nownes or - twgueasi' | DECREASE I 
PLANTS ; ; STRIP 
Original Core Strip 
Petioles partly flaccid 
bE 0 ee cee 30.0 | 31.6 | 20.4 5.3 percent] 2.0 percent 
Petioles turgid 
Bb 82s 20.0 ati7 8.5 I.0 
ab tees 24.7 26.8 24.5 8.4 0.8 
B62 990. 5; 30.0 32.5 2 3:3 I.0 
Average of Dien petioles is as ee 8.4 0.9 
As shown in the table, the core is capable of greater elongation when 
turgid, but the cortex will contract more when flaccid. The possibility 
of change in length in the core is greater than in the cortex because the 
former is more vascular. In the petiole, in nature, under turgid condi- 
tions, the sum of the possibilities of change in length of the tension- 
producing elements is greater than when the organ is flaccid, consequently 
greater tissue tension is present under turgid conditions.—FRANK 
Gates, Los Bajos, P.I. 
